During surgical procedures, patients may be placed under anesthesia. As a result, the body's natural thermoregulatory mechanisms may be affected and systemic vasodilation may occur. Systemic dilation counteracts the body's natural heat retention mechanism and allows body heat to flow down a concentration gradient to the extremities, where heat is lost to the environment. As a result, the patient is at risk of perioperative hypothermia. Medical complications may result from perioperative hypothermia and may include peri-operative and post-operative complications, including for example, increased wound infection rates, metabolic acidosis, respiratory distress, cardiovascular effects, surgical bleeding, and increased risk of mortality. Therefore, a need exists for patient warming devices that actively warm the patient to maintain normothermia, prevent perioperative hypothermia, and/or treat hypothermia.
Forced air convective warming blankets, large wraps, or pads are commonly used to cover various parts of the body. These warming devices generally cover a large portion of the body, restricting access to the patient in covered areas. A surgeon, or other medical staff, requiring access to the covered portions of the body in order to introduce surgical elements, such as intravenous feed lines, pulse oximetry probes, needles, vitals monitoring instruments, and other medical instruments, may need to reposition or remove the warming device. Removal and repositioning of the device not only increases the time required for the surgical procedure, but may also significantly reduce heat transfer to the patient during that time. Moreover, control systems for forced air convective devices tend to generate loud noise that may distract or interfere with communication between surgeons and medical personnel in an operating room.
Active warming devices also tend to cause stippling on patients' skin. Stippling may cause pain in geriatric or elderly patients, pediatric or very young patients, or patients with sensitive skin. Stippling is also unsightly, and may evoke unnecessary concern from a patient and from friends and family members who observe the stippling on the patient's skin.
Deep vein thrombosis (DVT) is another common concern during surgical operations. Compression devices are commonly used to prevent deep vein thrombosis by applying intermittent pneumatic compression to a patient's lower extremities, such as the legs and feet of a patient. The intermittent pressure promotes venous blood flow so as to prevent deep vein thrombosis. DVT prevention devices may use negative pressure, or vacuum pressure, to apply compression, which requires a seal around the patient's extremity and does not allow for access to the underlying surface of the patient. Applying negative pressure, or vacuum pressure, for DVT prevention also tends to increase stippling.
During surgical procedures, it is common to use a device for preventing deep vein thrombosis and a separate device for active patient warming on different body portions of the patient. For example, a device for preventing deep vein thrombosis may be attached to the patient's leg, while a device for active patient warming may be attached to another part of the patient's body. Therefore, there is a need and/or desire in the art to provide devices and methods for patient care that will promote and maintain normothermia and/or treat hypothermia while providing access to portions of the patient's body underlying the device, preventing deep vein thrombosis, and avoiding or minimizing stippling, impressed wrinkles, or the like on a patient's skin.